In a known apparatus of this type a chain guide rail is provided on the outside conveying chain remote from the vehicle wheel. This chain guide rail is constructed as an angle section, the horizontal leg of the angle section being welded to the supporting structure of the conveying apparatus while the vertical leg is arranged at a slight distance from the outside of the chain and serves to guide the chain. In the known apparatus the vertical leg is bent above the associated chain 90.degree. towards the vehicle wheel and extends over more than the chain width. The inner edge, facing the vehicle wheel, of this horizontal bent part is rolled in and forms the side guide for the vehicle wheel. The rolled-in edge extends so far towards the center of the travel path that the chain is covered completely at the top and direct contact between the vehicle wheel and the chain is impossible. The side guides hold the wheel in the track, said wheel rolling along between the side guides on the travel path and being pushed by the driving roll. If, however, the vehicle wheel is turned or strikes strongly against the side guide there is so much friction that the wheel rolls over the side guide and the vehicle thereby drives off the track. This can lead to considerable damage to the vehicle and/or the washing device (this including a drying device located downstream thereof). In order to prevent this overrolling of the side guides, the side guides must be arranged at a relatively long distance from the travel path or, in other words, a relatively great height above the travel path. This leads to low-slung vehicles with little ground clearance no longer being washable or at least being likely to suffer damage to the vehicle and possibly also to inflict damage on the conveying apparatus. Furthermore, the wheel rims of vehicles which are provided with low section tires, are damaged by direct friction of the rims against the side guides, because the side guides are arranged at a height of approximately 80 to 120 mm from the travel path, while the rims of low section tires are at a distance of only 50 to 60 mm from the travel path. So that the vehicle wheels can be steered as little as possible, the track width i.e. the internal distance between the two side guides, should be as small as possible. Because of the above-mentioned low section tires and larger vehicles with correspondingly wider tires, the track width has, however, to be made relatively large. This then leads to difficulties with smaller vehicles with narrow tires, since then the vehicle wheels can again be steered at a relatively large angle. Moreover, the side guides require additional structural expenditure, since they are provided in addition to the chain guides and must, because of the possibility of overrolling by the vehicle wheel, be constructed to be relatively stable. Finally, high side guides prevent wheel rim washing brushes from reaching the wheel rims when the tires are the above-mentioned low section tires. The rims are only insufficiently washed at the outer edge and it is possible, moreover, by contact between the washing brush and the side guides, for the washing brush to be damaged or to suffer increased wear.
Therefore, the problem on which the invention is based is that of providing an apparatus for conveying motor vehicles into washing installations of the above-mentioned type, which prevents with certainty a vehicle from finding its way off the track, which is suited to damage-free conveyance of vehicles both with very wide tires and low section tires and which is nevertheless of simpler construction and therefore cheaper to produce and easier to maintain.
This is achieved according to the invention in that the conveying chains themselves or elements moved synchronously with the conveying chains are constructed as side guides for the vehicle wheel and in that the chain guide rails are so arranged and constructed that direct contact between the vehicle wheel and the conveying chains or the synchronously moved elements is possible.
In contrast to the previous prior art, in which the side guides were also intended to prevent contact between the vehicle wheel and the conveying chains, the invention dispenses completely with such stationary side guides. Instead, in the apparatus according to the invention direct contact between the vehicle wheel and the conveying chains is made by dispensing with additional side guides and by appropriate construction of the chain guide rails. The conveying chains themselves form the side guides. They may at the same time be arranged at a relatively long distance from each other, such that even vehicles with very wide tires or low section tires fit without problem between the chains. Furthermore, it is possible to arrange the conveying chains at a height so small a distance from the travel path that upper edges of the conveying chains are arranged at a height of at most approximately 60 mm, but also of less, for example only 40 mm, from the travel path. The low height of the conveying chains eliminates damage to the wheel rims of low section tires. However, it was noted surprisingly that the conveying chains serving as side guides hold the vehicle in the track and overrolling of the conveying chains by the vehicle does not occur even when the vehicle wheel is greatly turned. It was noted that although a highly turned vehicle wheel is pushed onto one of the conveying chains under the action of the driving roll, it does not then roll over the conveying chain. The vehicle wheel is lifted hereby from the travel path and then lies only on the conveying chain and the driving roll. However, as soon as the vehicle wheel loses contact with the travel path, it stops rotating. Then, no more relative movement takes place between the wheel and the conveying chain moving at the same speed as the vehicle, such that although the vehicle wheel rolls partially onto the conveying chain it does not roll over it. Since the vehicle wheel rolls only very slightly onto the conveying chain before it loses contact with the travel path, the conveying chain still offers sufficient lateral guidance, which also prevents the turned wheel on the other side of the vehicle, which wheel is not moved and guided by the conveying apparatus, from pulling the vehicle off the track. Rather, it was noted that the vehicle is held on the track by the conveying chain and the turned, unguided wheel begins to skid. However, experience has shown that this extreme case only arises with very great manual turning of the vehicle wheels. When the steering wheel is released the vehicle wheels straighten themselves and the vehicle is conveyed on normally. If the driver ceases completely to turn the steering wheel, it may be noted that the vehicle wheel does not roll onto one of the conveying chains at all. Since in the apparatus according to the invention the conveying chains also assume the function of side guides, additional side guides are wholly unnecessary, which makes the construction simpler and production cheaper. Furthermore, the conveying chains can be more easily maintained and lubricated, since they are easily accessible. Because of the low height of the conveying chains the wheel rim washing brushes can also clean the rims of low section tires better and the risk of damage or premature wear to these wheel rim washing brushes through contact with side guides arranged high above the travel path does not arise.